The authors of this book discuss the use of organosilanes as anchoring layers for biomolecules on different materials. The biofunctionalization of organosilanes and their applications are also examined. Moreover, heterogenizing of organocatalysts is one of the big issues during this decade and mesoporous silica seems to be the best candidate in viewpoint of easy catalyst preparation and support stability. The synthesis pathways of organofunctionalized mesoporous materials are analyzed. In addition, sol-gel derived hybrid organic/inorganic (O/I) nanocomposites are largely exploited in materials technology, due to the synergic merge at the molecular scale of the components characteristics through a large extent of phase interaction. A review of the main results are reported here on the preparation. In other chapters, the authors explore the bioapplications of silica-based glasses prepared from functionalized organosilane precursses and provide some examples of newly developed Si-Si or Si-H bond containing compounds, which exhibit a high reactivity both in Free Radical Polymerization (FRP) and in Free Radical Promoted Cationic Polymerization (FRPCP) under air.